Wireless Communication Apparatus and Wireless Communication Method
A wireless communication apparatus wherein the data amount of feedback information can be reduced, while a high throughput being maintained. In this apparatus, a CSI (Channel State Information) processing part ( 38 ) generates a CSI frame based on an SNR (Signal power to Noise power Ratio) for each of measured subcarriers, and a CSI transmission control part ( 39 ) generates a timing signal and control information required for generating the CSI frame, and controls the CSI processing part ( 38 ). The CSI processing part ( 38 ) generates a first frame (CSI 1 ) which comprises the CSI of a subcarrier whose SNR variation amount is less than a threshold value, in a generation period that is greater than the generation period of a second frame (CSI 2 ) comprising the CSI of a subcarrier whose SNR variation amount is equal to or greater than the threshold value.
1 . A radio communication apparatus comprising:
a receiving section that receives a multicarrier signal composed of a plurality of subcarriers;
a measuring section that measures a quality level per subcarrier or per segment of the multicarrier signal;
a comparison section that compares the quality level or an amount of variation of the quality level with a threshold value; and
a transmitting section that transmits CSI or modulation parameters of some subcarriers or some segments for which the quality level is less than the threshold value, or of some subcarriers or some segments for which the amount of variation exceeds the threshold value, using a first feedback period, and transmits CSI or modulation parameters of all subcarriers or all segments using a second feedback period greater than the first feedback period.
2 . The radio communication apparatus according to claim 1 , wherein the transmitting section transmits a comparison result of the comparison section as CSI.
3 . The radio communication apparatus according to claim 1 , further comprising a setting section that sets the threshold value using an average value or a median value of the quality levels of the plurality of subcarriers.
4 . The radio communication apparatus according to claim 1 , further comprising a generation section that generates a first frame composed of CSI or modulation parameters of a subcarrier or segment for which the quality level exceeds the threshold value, or of a subcarrier or segment for which the amount of variation is less than the threshold value, and generates a second frame composed of CSI or modulation parameters of a subcarrier or segment for which the quality level is less than the threshold value, or of a subcarrier or segment for which the amount of variation exceeds the threshold value,
wherein the transmitting section transmits the first frame using a feedback period that is an integral multiple of a feedback period of the second frame.
5 . A radio communication terminal apparatus comprising the radio communication apparatus according to claim 1 .
6 . A radio communication base station apparatus comprising the radio communication apparatus according to claim 1 .
7 . A radio communication method comprising:
a receiving step of receiving a multicarrier signal composed of a plurality of subcarriers;
a measuring step of measuring a quality level per subcarrier or per segment of the multicarrier signal;
a comparison step of comparing the quality level or an amount of variation of the quality level with a threshold value; and
a transmitting step of transmitting CSI or modulation parameters of some subcarriers or some segments for which the quality level is less than the threshold value, or of some subcarriers or some segments for which the amount of variation exceeds the threshold value, using a first feedback period, and transmitting CSI or modulation parameters of all subcarriers or all segments using a second feedback period greater than the first feedback period.